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प्रश्न
Some words (underlined) in the following sentence is jumbled up. Write them in their correct form.
Some substances on combustion produce thea and mafel.
उत्तर
Some substances on combustion produce heat and flame.
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संबंधित प्रश्न
Give reasons.
Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.
Combustion is a chemical reaction in which and substance react with ______.
The substance expected to have the highest ignition temperature out of the following is
Two glass jars A and B are filled with carbon dioxide and oxygen gases respectively. In each jar, a lighted candle is placed simultaneously. In which jar, will the candle remain lighted for a longer time and why?
Match the items of Column A with the items of Column B.
| Column A | Column B |
| (a) Oxides of sulphur and nitrogen | (i) fire extinguisher |
| (b) CNG | (ii) incomplete combustion of coal |
| (c) Oxygen | (iii) very low ignition temperature |
| (d) inflammable substance | (iv) acid rain |
| (e) carbon dioxide | (v) necessary for combustion |
| (f) carbon monoxide | (vi) fuel for automobiles |
People usually keep angithi/burning coal in their closed rooms during winter season. Why is it advised to keep the door open?
Write True/False against the following statement and also correct the false statement.
A physical process in which a substance reacts with oxygen to give off heat is called combustion.
Complete the crossword with the help of the clues.
Across
1. Non-metal which catches fire if exposed to air. (10)
3. The lowest temperature at which a substance catches fire is called its ______ temperature. (8)
5. The most common fire extinguisher. (5)
Down
2. A chemical process in which a substance reacts with oxygen to give off heat. (10)
4. Petrol is used as a ______ in automobiles. (4)
6. It is as hard as stone and black in colour. (4)
Fill in the blanks using the word given in the box.
| ignition | petrol | combustion | calorific value | combustible | combustible |
Wood, paper, CNG are ______ substances.
Fill in the blanks using the words given in the box.
| ignition | petrol | combustion | calorific value | combustible | combustible |
Ignition temperature of ______ is lower than that of wood.
